In U.S. Pat. No. 6,030,538, issued in Feb. 29, 2000 entitled “Method and Apparatus for Dewatering Previously-Dewatered Municipal Waste-Water Sludges Using High Electrical Voltages”, there is disclosed a system and method for dewatering and treating sludge emanating from municipal waste, or pulp-waste from a paper mill, as well as treating animal and plant waste. In that patent, the method for breaking down the sludge is to subject it to electroporation, which incorporates nonarcing, cyclical high voltages in the range of between 15 kv./cm and 100 kv./cm. which break down inter-cellular and intracellular molecular bonds of waste-activated sludge (WAS), to thus release inter-cellular and intracellular water, whereby the WAS is rendered inactive and greatly reduced in mass.
The viability and effectiveness of pulsed electric field (PEF) for disrupting the biomass in waste activated sludge (WAS) derived from municipal wastewater treatment has been proven in laboratory testing and on-site pilot projects. While there was no significant increase in the solids content of dewatered sludge, the quantity of WAS needing disposal was estimated to be significantly reduced. The pilot plant for testing at one or two wastewater treatment plants that generate WAS has been developed and deployed. A pulsed electric field (PEF) system that could handle 0.5 to 1.0 pgm WAS feed was designed. This requires an 8 kw power supply capable of generating 30 kV and pulse generator capable of handling 50 amp peak, current, bi-polar pulses, square wave, 10 μs pulse width, and 3000 pulses/second (pps).